A strong opioid painkiller (controlled drug)
Oxycodone
A strong opioid painkiller for severe pain, available in fast-acting and slow-release forms — effective but carrying real risks of constipation, drowsiness, dependence and breathing problems.
What is Oxycodone?
Oxycodone is a strong opioid painkiller used for moderate-to-severe pain that milder painkillers cannot control, such as after surgery or in cancer pain. It is a powerful medicine that needs careful use under medical supervision.
Education and reference only. This is a plain-language guide to Oxycodone — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Oxycodone is a strong opioid painkiller used for moderate-to-severe pain that milder painkillers cannot control — for example after surgery, in cancer pain, or in some other serious pain. It comes in two patterns: immediate-release (fast-acting, for quick or breakthrough relief) and modified-release (slow, steady relief over a longer period for background pain). In the UK the immediate-release versions include OxyNorm and Shortec, and the slow-release versions include OxyContin and Longtec; the active ingredient is the same. It is a controlled drug, prescribed and stored under strict rules, and used carefully because of its risks.
How it works
Oxycodone attaches to opioid receptors in the brain, spinal cord and gut, dampening the pain signals travelling to the brain and changing how pain is perceived, so it feels less intense and distressing. The same action on these receptors slows the bowel (causing constipation), can make breathing slower and shallower (the main danger in overdose), and produces drowsiness and, over time, tolerance and physical dependence. This is why the effective relief comes alongside a need for caution and monitoring.
Company & origin
Originated / developed by: Originally synthesized at the University of Frankfurt; OxyContin developed by Purdue Pharma.
Oxycodone was first synthesized in 1916 in Germany by Martin Freund and Edmund Speyer from thebaine. The modern controlled-release formulation OxyContin was developed and launched by Purdue Pharma (USA) in 1996.
Practical use
How to take Oxycodone
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it exactly as prescribed and never more often than directed.
- It commonly causes constipation, so your doctor may suggest a laxative, and it can also cause drowsiness.
- Do not drink alcohol or take other sedating medicines with it, as together they can dangerously slow breathing.
- Do not drive or operate machinery if you feel drowsy or lightheaded.
- It can be against the law to drive if this medicine affects you — do not drive when you first start it or after any dose change until you know how it affects you.
- Do not stop suddenly after regular use, as this can cause withdrawal; your doctor will reduce it gradually.
- Keep it locked away safely and never share it, as it carries a risk of dependence and misuse.
Weighing it up
Advantages & disadvantages of Oxycodone
Advantages
- Effective for severe pain that weaker painkillers cannot control.
- Available in different forms for short-term and longer-lasting pain relief.
- A valuable option in cancer pain and after major surgery when used appropriately.
Disadvantages
- Can cause dependence and addiction, and tolerance can build with longer use.
- Frequently causes constipation, drowsiness and nausea.
- Combined with alcohol or other sedatives it can dangerously slow breathing.
- Must not be stopped abruptly after regular use because of withdrawal effects.
Practical use
Good to know
The two forms are used together deliberately: a slow-release tablet provides steady background relief, while a fast-acting form covers flares of "breakthrough" pain — and they must not be confused. Constipation is almost universal, so a laxative is usually started at the same time. Drowsiness affects driving and concentration, especially when starting or increasing. The body adapts over time, so the same effect may need more medicine (tolerance) and stopping suddenly after regular use can cause withdrawal — so it is reduced gradually. It must not be combined casually with other sedatives because of the danger to breathing.
Who should not take it / use with caution
- People with significant breathing problems or an acute asthma attack, as opioids further depress breathing.
- People who are heavily intoxicated with alcohol, have a head injury with raised pressure in the skull, or have a paralysed/obstructed bowel.
- Used with great caution in older or frail people, in significant liver or kidney disease, in those with sleep apnoea, and in anyone with a history of substance dependence; care too in pregnancy and breastfeeding.
Monitoring
- Pain control and whether the dose still suits
- Side effects — especially constipation, drowsiness and breathing
- Signs of tolerance or dependence, and a plan to review and reduce when possible
Side effects
- Constipation (almost always — usually needs a laxative), nausea and vomiting (often easing after the first days), and drowsiness.
- Dizziness, dry mouth, itching, and confusion especially in older people.
- Most seriously, slow or shallow breathing (respiratory depression), which can be life-threatening in overdose — signs include extreme drowsiness, pinpoint pupils and very slow breathing, and need emergency help.
Key interactions
- Benzodiazepines and "z-drugs", gabapentin and pregabalin, and alcohol all add to sedation and the risk of dangerous, slowed breathing — a particularly important and sometimes fatal combination.
- Other sedating medicines, including some antidepressants, antipsychotics and antihistamines, add to drowsiness.
- Some medicines change its levels (certain antifungals, antibiotics and HIV treatments can raise them); care also with other opioids and with medicines affecting serotonin.
Available as: Immediate-release capsules and liquid (fast-acting), modified-release tablets (slow, steady relief), and an injection used in hospital.
Answers
Oxycodone: frequently asked questions
What's the difference between OxyContin and OxyNorm?
They contain the same active ingredient, oxycodone, but in different forms. OxyContin (and Longtec) are modified-release, giving slow, steady relief over a longer period for constant background pain. OxyNorm (and Shortec) are immediate-release, working quickly for breakthrough pain. They are often used together but must not be mixed up, as the slow-release form is not for quick relief.
Will I become addicted?
Taken as prescribed for genuine pain, addiction is less likely, but the body does adapt: with regular use you can develop tolerance (needing more for the same effect) and physical dependence (withdrawal if it stops suddenly), which are not the same as addiction. This is why it is reviewed regularly, reduced gradually rather than stopped abruptly, and used at the lowest effective amount.
Why must I avoid it with sleeping tablets or pregabalin?
Opioids, benzodiazepines, "z-drug" sleeping tablets, gabapentin/pregabalin and alcohol all slow breathing, and combining them sharply raises the risk of dangerously slow or stopped breathing — a leading cause of opioid deaths. If you take any of these, your prescriber needs to know so the combination can be avoided or managed very carefully.
Why do I need a laxative with it?
Opioids slow the bowel, so constipation is almost universal with oxycodone and rarely settles on its own. A laxative is usually started at the same time to prevent it. Keeping hydrated, eating fibre and staying active also help. Tell your team if constipation becomes severe or you stop opening your bowels.
What is the difference between oxycodone and the brands?
They are the same active ingredient — oxycodone is the generic name, and OxyContin, OxyNorm, Longtec and Shortec are brands. The key thing is not brand versus generic but immediate-release versus modified-release, as these behave very differently. Always check which form you have been given.
The wider class
About Opioid analgesics
Oxycodone belongs to the opioid analgesics class. For how the class as a whole works, its shared safety principles and monitoring, see the full guide.
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Authoritative sources
- BNF: Oxycodone hydrochloride.
- electronic Medicines Compendium (SmPC): Oxycodone (OxyContin/OxyNorm).
- NICE: Controlled drugs — safe use and management.
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